A man in a yeti costume in the Himalayas, Nepal, in this photograph from 1992. 'A team of scientists recently sorted through 36 samples of supposed yeti fur using the resources of modern genetics.' Photograph: Sipa Press/Rex Features

Scientific hunters for the yeti are easy to recognise: they want to bring back the corpse of some other animal altogether. Most recently, a team led by Professor Bryan Sykes of Oxford sorted through 36 samples of supposed yeti fur using the resources of modern genetics and reported their findings with the full scholarly apparatus, including a footnote referencing Tintin in Tibet as the source of "Captain Haddock's suspicions that the yeti was an ungulate".

They may not be entirely serious here, although the headline finding of the study is fascinating – in two of the Himalayan samples there is evidence of mitochondrial DNA sequences from polar bears, which match samples taken earlier on the high Arctic island of Svalbard, 4,000 miles away. Since today there are no polar bears over at least 3,000 miles of that distance, they have produced a delightful puzzle. It's a dim memory of improbable sexual encounters in the Siberian past, rather like the discovery of Denisovan DNA fragments in modern humans.

But that is the only human characteristic of the yeti that the team has discovered. The fur comes from a bear and all the other furs examined come from antelopes, cows and other even less romantic animals, just as Captain Haddock hypothesised. Another lovely fantasy crushed.

But why bother? Have scientists nothing better to do with their time? There are a couple of reasonable answers to this question.

Some myths are of course actively pernicious. The stories spread by Aids denialists or anti-vaccine cranks have helped kill thousands if not tens of thousands of people. It's a public duty to go after them.

Other stories would be great fun if they were true and it would be wonderful to prove they were. Of course, judging what are going to be the right questions is a talent that scientists need, at least as much as the more obvious gift of finding the right answers. The existence of a yeti is not a scientific question of the first importance. Even if one were found, it wouldn't raise nearly as many interesting further questions as did the discovery of the "Hobbit" on Flores.

That's not the only problem, though. There's a sense in which the pernicious myths are spread by an appeal to sentiments that are not just anti-science, but anti-scientists. This is a reasonable and unremarkable standpoint: science, like anything else humans do, is driven by the imagination and appeals to certain temperaments more than others. Some of those to whom science is unappealing also find the scientific style of imagination repulsive. Poets did not make themselves popular or honoured by claiming to be the unacknowledged legislators of mankind; scientists don't do themselves any favours by claiming to be the arbiters of what is real or not.

As Mary Midgley points out, the word "real" is ambiguous. Sometimes it's useful. "Did you really mean that?" or even, "Is that real coffee". At other times it's only flannel, in a real sense. And sometimes it doesn't make any sense at all. "Is God real?" The confidence of the answers is in inverse proportion to their use.

Normal people – well, everybody, actually – are adept at bouncing through these different "realities" like lumberjacks bounding over spinning logs. We live quite comfortably in worlds where yetis do and don't exist, where they're real in stories and not in the Himalayas. The only dangerous scientists are those who don't understand this or don't believe it's true of themselves, and that they only believe true facts. You couldn't accuse these latest yeti hunters of that. The reference to Tintin proves it.